Under armor underwear or underpants (cold or all purpose gear) depending on temperature and similar top with jacket. A hat or hoodie under my helmet, and full fingered gloves if it cold. The less clothes to absorb liquid the better. Keep pedaling, and once you are wet your wet, so don't waste too much time avoiding it.
It rains/Snows/Sleets all the time here.
http://alphabluetech.com/kj2/cyclinghome.php
Go there and scroll all the way down and click play on the very last video.
Here is a video from some of the rain on tour. Some of it was ice cold, the downhill was sleet as you can see and hail in KC. Not too mention tornadoes and standard rainstorms.